Model railroading is an area where a lot of different weathering techniques and materials come into play and a collection of tips can be a real help.
Many model railroaders in particular feel no structure, engine or piece of rolling stock ever makes it on the stage in of their basement empire unless it has been grunged, rusted or otherwise had its "new" look killed.
1. Weathering rock and concrete walls
Begin by dry brushing a liberal coat of mud coloring along the bottom which represents years of paint splattering. Give your concrete a warmer look by dry brushing with Earth. In the case of concrete loading docks dry brush with Grimy Black in a few spots on the vertical face of the loading dock, using vertical brush strokes and applying it mostly near the top to give the appearance of grease or oil which had run down from the dock.
India ink dripped into half a film canister of alcohol makes a good wash to bring out depth and texture of wall surfaces.
2. Simulate The Results of Rust When applying rust to model railroad cars, metal ships or other vehicles, figure where your gash, scrape or dent might be. Remember, forklift operators will sometimes use their forks to open or close the box car door, thus creating big scrapes along the sides of the doors. Anchors also will cause scrapes and gashes, but remember ships are better manitained than rolling stock. With a fine tip brush, apply in a downward motion from your gash, scrape or dent with your rust color.
Make multiple passes with different shades and colors of rust to acheive the right result.
3. Water Streaking 1. With various brush sizes, apply in a downward motion from the top of the car, your thinned polly scale paint, and work it into the grooves and such. It's best to have a few shades of grime thinned to give you a better look. The acrylic polly scale paint can be thinned with water giving you some real nice shades. 2. Your car should look dirty and you should now have streaks. There will be some streaks that are lighter or darker than others if you did the streaks using different shades. If all of your streaks have the same opacity, then it will not look realistic. 3. Try to break up the pattern of your streaks so that it looks random. "The more random, The more real.
4. The effects of age on building roofs Since we usually are looking down at model structures, pay careful attention to roof finish and details. Flat roofs may be covered with tar paper composed of tissue paper cut in strips or "rolls" and affixed with grimy black paint. Seams or the splash onto the wall may be done with super glossy black paint. Or a roof might be painted black or brown and dusted with a fine talc powder or very fine ballast or sand to replicate a graveled surface. A fine sandpaper, perhaps the same piece used to sand the walls, can be cut and glued down. Detail chimneys, giving thought to where they would logically be in the roof, and drilling out the flues and painting them black. Add trap doors, sky lights, vents, or puddles.
5. Painting and Weathering Track We often pay more attention to detailing rolling stock, locomotives and structures than the little things like track leaving bright nickel-silver rails and shiny plastic ties.
Simply painting the track and ties with a coat of flat dark brown is a major improvement. Like any other type of weathering, you can go as far as you desire. Paint ties individually with different shades, splash on a little India ink to resemble dripped oil.
For the most part, paining and weathering trackage is easier and less messy if you do it before it becomes part of the landscape.
Track appearance is important, but not as vital as locomotive electrical contact. For good contact it’s important to ensure that you can easily remove paint from the railheads.
Turnouts require special care to avoid gumming up the moving parts with paint. Before painting, mask along the points and throw bar. Brush-paint these areas later.